CN103576510A - Developing device, image forming apparatus and image forming method - Google Patents
Developing device, image forming apparatus and image forming method Download PDFInfo
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- CN103576510A CN103576510A CN201310114504.1A CN201310114504A CN103576510A CN 103576510 A CN103576510 A CN 103576510A CN 201310114504 A CN201310114504 A CN 201310114504A CN 103576510 A CN103576510 A CN 103576510A
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
- G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
- G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush
- G03G15/0921—Details concerning the magnetic brush roller structure, e.g. magnet configuration
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G13/00—Electrographic processes using a charge pattern
- G03G13/06—Developing
- G03G13/08—Developing using a solid developer, e.g. powder developer
- G03G13/09—Developing using a solid developer, e.g. powder developer using magnetic brush
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- General Physics & Mathematics (AREA)
- Magnetic Brush Developing In Electrophotography (AREA)
- Dry Development In Electrophotography (AREA)
Abstract
Provided is a developing device including a pair of developer holding members that include a pair of cylinder members, which are disposed close to each other and rotate in the same direction at an adjacent gap at which both cylinder members are in close proximity, and a pair of magnetic force generation sections which are provided inside the pair of cylinder members respectively and generate magnetic forces for holding a developer on the cylinder members, and a pair of developing magnetic poles that are provided in the pair of magnetic force generation sections respectively, are disposed to be opposed to a latent image holding member, and are set to have the same polarity.
Description
Technical field
The present invention relates to developing apparatus, image forming apparatus and image forming method.
Background technology
JP-A-2007-47639(patent documentation 1) a kind of developing apparatus is disclosed, in this developing apparatus, rotate forward developer roll and there is opposed polarity with the magnetic pole of the opposed reverse rotation developer roll of limiting member, and at least one transmission magnetic pole is arranged between the magnetic pole towards adjustment means and the magnetic pole of Graph-Oriented as retaining member in any one of rotating forward in developer roll and reverse rotation developer roll.
Summary of the invention
Between developer on the development magnetic pole of a pair of developer retaining member that the object of the invention is to increase sub-image retaining member and arrange close to each other along the contact width of circumferential direction.
According to a first aspect of the invention, a kind of developing apparatus is provided, described developing apparatus comprises: a pair of developer retaining member, this a pair of developer retaining member comprises a pair of cylindrical member and a pair of magnetic force generating unit, this a pair of cylindrical member arranges close to each other and rotates along equidirectional at adjacent segment place, at described adjacent segment place, these two described cylindrical members closely approach, and this pair of magnetic force generating unit is arranged on respectively in described a pair of cylindrical member and produces for developer being remained on to the magnetic force on described cylindrical member; And a pair of development magnetic pole, this pair of development magnetic pole is separately positioned in described a pair of magnetic force generating unit, is arranged to sub-image retaining member opposedly, and sets for and has identical polarity.
According to a second aspect of the invention, according in the developing apparatus of first aspect, described a pair of magnetic force generating unit is provided with a pair of conveying magnetic pole, the position arranged opposite that corresponds respectively to described adjacent segment of this pair of delivery magnetic utmost point and set for and there is contrary polarity, and between described conveying magnetic pole and described development magnetic pole, one or more magnetic poles are set, make to there is different polarity when described development magnetic pole and described delivery magnetic have the magnetic pole that identical polarity chron is adjacent.
According to a third aspect of the invention we, according in the developing apparatus of first aspect or second aspect, and described sub-image retaining member has cylindrical shape substantially, and the center of described a pair of development magnetic pole is separately positioned on the upstream along sense of rotation of a straight dashed line, described straight dashed line is through the rotation center of described cylindrical member and the rotation center of the described sub-image retaining member of cylindrical shape substantially.
According to a forth aspect of the invention, provide a kind of image forming apparatus, described image forming apparatus comprises: the developing apparatus according to first aspect to the either side in the third aspect; Sub-image retaining member, described sub-image retaining member has for the surface that forms sub-image, and described sub-image is revealed as toner image by described developing apparatus; And transfer section, described transfer section is transferred to the lip-deep toner image that is formed on described sub-image retaining member on transfer printing target object.
According to a fifth aspect of the invention, a kind of image forming method is provided, and described image forming method comprises: make by according to first aspect to the developing apparatus of the either side in the third aspect, the lip-deep sub-image that is formed on sub-image retaining member being revealed as to toner image; And the toner image being formed on described sub-image retaining member is transferred on transfer printing target object.
According to a first aspect of the invention, the situation with the development magnetic pole of the magnetic force generating unit of a pair of developer retaining member wherein with opposed polarity is compared, and can increase the contact width along circumferential direction between the developer on sub-image retaining member and development magnetic pole.
According to a second aspect of the invention, thering is the development magnetic pole of identical polar and carrying the structure that magnetic pole is not set between magnetic pole to compare, improved the ability that transmits the developer that is sent to development magnetic pole with wherein.
According to a third aspect of the invention we, the situation with the development magnetic pole of the magnetic force generating unit of a pair of developer retaining member wherein with opposed polarity is compared, the center of the development magnetic pole of a pair of magnetic force generating unit is arranged in the structure through the upstream along sense of rotation of the straight dashed line of the rotation center of sub-image retaining member and the rotation center of cylindrical member therein, can increase the contact width along circumferential direction between the developer on sub-image retaining member and development magnetic pole.
The according to a forth aspect of the invention with five aspect, compare with wherein not arranging according to first aspect to the situation of the developing apparatus of the either side in the third aspect, can suppress the image deflects that caused by the little contact width along circumferential direction between the developer on development magnetic pole and sub-image retaining member.
Accompanying drawing explanation
To describe illustrative embodiments of the present invention in detail based on following figure, in accompanying drawing:
Fig. 1 is the structural map that the structure of image forming apparatus is according to an illustrative embodiment of the invention shown;
Fig. 2 is the structural map that the structure that is arranged on the developing apparatus in the image forming apparatus shown in Fig. 1 is according to an illustrative embodiment of the invention shown;
Fig. 3 is the magnetic flux distribution figure of distribution that the magnetic flux density of rotating forward developer roll and reverse rotation developer roll of the developing apparatus shown in Fig. 2 is shown;
Fig. 4 is the key diagram of half breadth that the development magnetic pole that rotates forward developer roll and reverse rotation developer roll of the developing apparatus shown in Fig. 2 is shown;
Fig. 5 is the magnetic figure of direction that the magnetic line of force that rotates forward developer roll and reverse rotation developer roll of the developing apparatus shown in Fig. 2 is shown;
Fig. 6 is the magnetic figure that in the comparative example direction of the magnetic line of force be shown corresponding with Fig. 5, and in this comparative example, the development magnetic pole that rotates forward developer roll and reverse rotation developer roll has opposed polarity;
Fig. 7 A and Fig. 7 B are the curve maps of half breadth of setting the development magnetic pole of 40 °, 30 ° and 25 ° in the structure that is provided with reverse rotation developer roll for, wherein Fig. 7 A illustrates development interlock width and by the develop curve map of the relation the amount MOS of toner of the per unit area to photoreceptor of reverse rotation developer roll, and Fig. 7 B is the curve map that the relation between MOS and developing performance DQA is shown;
Fig. 8 is the curve map that is illustrated in the relation between MOS and development interlock width in the structure of 1-MAG, homopolarity 2-MAG and heteropole 2-MAG; And
Fig. 9 is the curve map that is illustrated in the relation between MOS and developing performance DQA in the structure of 1-MAG, homopolarity 2-MAG and heteropole 2-MAG.
Embodiment
With reference to Fig. 1 to 5 description developing apparatus according to an illustrative embodiment of the invention and the example of image forming apparatus.It should be noted, the arrow UP shown in figure represents vertically to upside.
Image forming apparatus
First, with reference to the unitary construction of Fig. 1 Description Image forming device.
As shown in Figure 1, image forming apparatus 10 comprises: photoreceptor 12, and this photoreceptor has the drum shape as the example of sub-image retaining member; Charging device 14, this charging device is to the surface charging of photoreceptor 12; Exposure device 16, thus this exposure device forms electrostatic latent image based on view data with Ear Mucosa Treated by He Ne Laser Irradiation photoreceptor 12; Developing apparatus 18, this developing apparatus is optionally transferred on electrostatic latent image by toner and is made toner be revealed as toner image; Transfer roll 22, this transfer roll is for the lip-deep toner image of photoreceptor 12 being transferred to the example of the transfer section on the sheet element P of the example of the transfer printing target object (printed medium) being supplied along transfer path 20; Fixing device 24, thus this fixing device heats the toner image that pressurizes on sheet element P by image fixing to sheet element P; And cleaning device 26, this cleaning device cleans and after transfer printing toner image, remains in the toner on photoreceptor 12.It should be noted and will describe after a while developing apparatus 18(in detail referring to Fig. 2).
In addition, image forming apparatus 10 is covered by main body side cover 10B and top board 10A.In addition, the axle 10C that rotatably top board 10A is connected to main body side cover 10B is arranged on the bight of upper end of main body side cover 10B, and top board 10A makes the axle 10C rotation into rotation center in the direction of arrow A, thereby the inside of opening image forming apparatus 10.So the top board 10A of image forming apparatus 10 is opened, and can carry out various maintenance works (such as the supply of developer G and the replacing of each member).
In addition the paper feeder 40 of, supplying with one by one sheet element P is arranged on the downside of image forming apparatus 10 inside.Paper feeder 40 comprises the paper feeding member 41 for stacking a plurality of sheet element P.The sheet element P being stacked on paper feeding member 41 is picked up one by one by pick-up roller 42, and transmits one by one by being actuated to the paper-feed roll 44 of rotation and the separate roller 46 being arranged in paper feeding member 41.
And a plurality of transfer rollers 48 arrange along the transfer path 20 of sheet element P, and along transfer path 20, sheet element P are sent to the downstream (hereinafter referred to as downstream) along the direction of transfer of sheet element P.
In addition, above-mentioned fixing device 24 is arranged on the downstream of transfer path 20.Fixing device 24 comprises warm-up mill 24H and backer roll 24N, and by make sheet element P between warm-up mill 24H and backer roll 24N by the toner image being formed on sheet element P is fixed on sheet element P.
In addition, in the downstream of fixing device 24, distributing roller 38 is set, this distributing roller is discharged to the sheet element P with the toner image of photographic fixing thereon on the upper surface of top board 10A.
And, for manually supplying the manual feed pallet 32 of sheet element P, be arranged on a side of image forming apparatus 10.Meniscus outlet roller 34 is arranged on manual feed pallet 32, and separate roller 36 is arranged near outlet roller 34, and sheet element P is folded between this separate roller and outlet roller.
Image forming course
Next, by the image forming course of Description Image forming device 10.
First, charging device 14 is to the surface charging of photoreceptor 12.Then, the view data that the scanner of exposure device 16 based on by not shown reads and the data that send from outside are exposed the charging surface of photoreceptor 12, thereby form electrostatic latent image on the surface of photoreceptor 12.Then, thus developing apparatus 18 makes latent electrostatic image developing manifest the image as toner image.
On the other hand, sheet element P is sent transfer path 20 from paper feeding member 41 or manual feed pallet 32.Be sent the sheet element P of transfer path 20 through transfer section 31, this transfer section is formed on transfer roll 22 and keeps between the photoreceptor 12 of toner image, thereby toner image is transferred on sheet element P by transfer roll 22.Be transferred to toner image on sheet element P and pass between the backer roll 24N of fixing device 24 and warm-up mill 24H, and thus by photographic fixing to sheet element P.On it, photographic fixing has the sheet element P of toner image to be discharged on the upper surface of top board 10A by distributing roller 38.
Developing apparatus
Next, will the structure of developing apparatus 18 be described.It should be noted, the sense of rotation of photoreceptor 12 is indicated by arrow B, and the sense of rotation of reverse rotation developer roll 100 after a while to be stated indicated by arrow C, and the sense of rotation of rotating forward developer roll 200 after a while to be stated is indicated by arrow D.
As shown in Figure 2, developing apparatus 18 comprises shell 50, and this shell has the 50A of the portion that opens being arranged on photoreceptor 12 opposed positions.In shell 50 inside, as the reverse rotation developer roll 100 of the example of a pair of developer retaining member with rotate forward developer roll 200 and vertically arrange close to each other.
Reverse rotation developer roll 100 is arranged to the surface (outer peripheral face) of photoreceptor 12 opposed, and is rotating along the contrary direction (C direction) of the sense of rotation (B direction) with photoreceptor 12 with GP1 place, the opposed position of photoreceptor 12.In contrast, rotating forward developer roll 200, to be arranged in the downstream of the sense of rotation along photoreceptor 12 (B direction) and the surface (outer peripheral face) of photoreceptor 12 of reverse rotation developer roll 100 opposed, and with GP2 place, the opposed position of photoreceptor 12 along identical direction (D direction) rotation of the sense of rotation (B direction) with photoreceptor 12.In addition, reverse rotation developer roll 100 with rotate forward direction of motion that developer roll 200 rotation makes them at the adjacent segment GP3 place identical (will describe after a while reverse rotation developer roll 100 in detail and rotate forward developer roll 200) vertically arranging close to each other.
In being arranged on the downside of shell 50 inside and the spatial accommodation 50B of receiving photographic developer G, be provided with the first stirring transmission member 58 and second and stir transmission member 60, this first stirring transmission member and second stirs transmission member developer G is sent to and rotates forward developer roll 200.
Thereby first stirs transmission member 58 and second, stir transmission member 60 and arrange abreast rotating forward the downside of developer roll 200 (lower right side in figure) the developer G that circulates in planimetric map.Then, by rotating the first stirring transmission member 58 and second, stir transmission member 60, stir developer G, and along the direction of rotating forward the turning axle of developer roll 200, transmit simultaneously, and developer G is supplied to and rotates forward developer roll 200.It should be noted, the developer G using in developing apparatus 18 forms the two-component developing agent that the toner made by magnetic carrier particle and resin forms.
Layer forms the upstream along sense of rotation (D direction) that member 62 is arranged on the adjacent segment GP3 rotating forward on developer roll 200.It is board members that layer forms member 62, its cross sectional shape is rectangles along the normal direction of rotating forward the periphery of developer roll 200, and an end face 62A in the cross section of rectangular shape is arranged to towards the surface that rotates forward developer roll 200, at this end face with rotate forward between the surface of developer roll and there is space.Then, by making developer G form member 62 and rotate forward between developer roll 200 and pass at layer, make by the bed thickness that rotates forward the developer G that developer roll 200 keeps smooth.
Reverse rotation developer roll 100 and rotate forward the structure of developer roll 200
Next, will describe reverse rotation developer roll 100 in detail and rotate forward the structure of developer roll 200 after a while.It should be noted, in the following description of each magnetic pole, " S " refers to the S utmost point, and " N " refers to the N utmost point.
Reverse rotation developer roll 100 has the magnet roller (magnetic roller) 120 as the example of magnetic force generating unit, this magnet roller consists of development sleeve 100 and a plurality of magnetic poles that are arranged on these development sleeve 100 inside, and this development sleeve has the shape of tubular substantially as the example of cylindrical member.Equally, rotate forward developer roll 200 and also there is the magnet roller (magnetic roller) 220 as the example of magnetic force generating unit, this magnet roller consists of development sleeve 210 and a plurality of magnetic poles that are arranged on these development sleeve 210 inside, and this development sleeve has the shape of tubular substantially as the example of cylindrical member.In addition, the development sleeve 110 of reverse rotation developer roll 100 and the development sleeve 210 that rotates forward developer roll 200 are arranged to vertically with close distance towards each other, between the outer peripheral face of these two development sleeves, be formed with space, and development sleeve 110 and development sleeve 210 are above mentioned adjacent segment GP3 towards space each other therein.
The surface of the direction that the development sleeve 110 of reverse rotation developer roll 100 is arranged so that its turning axle along the direction of the turning axle of photoreceptor 12 towards this photoreceptor 12, and these development sleeve 110 rotations make contrary with the direction of motion of photoreceptor 12 with the opposed position of photoreceptor 12 its direction of motion of GP1 place (C direction).In addition, magnet roller 120 is arranged in development sleeve 110, and forms such magnetic field (referring to Fig. 3), and this magnetic field is circumferentially distributed in the outside of developer roll 100 by a plurality of magnetic poles of circumferential arrangement.
As shown in Figures 2 and 3, in the magnet roller 120 of reverse rotation developer roll 100, radially be provided with magnetic pole S1, magnetic pole N2, magnetic pole S3, magnetic pole N4, magnetic pole N5, magnetic pole S6 and magnetic pole N7, these magnetic poles are configured to seven permanent magnets, and the S utmost point of these permanent magnets or the N utmost point are along the face side that is circumferentially formed on magnet roller 120 of development sleeve 110.In addition, in reverse rotation developer roll 100, magnetic pole S1 is arranged on and GP1 place, the opposed position of photoreceptor 12, and this magnetic pole is development magnetic pole (development main pole).In addition, reverse rotation developer roll 100 by make developer G contacting with this photoreceptor 12 with GP1 place, the opposed position of photoreceptor 12 electrostatic latent image by developer G development photoreceptor 12.
For transmitting the magnetic pole N2 of developer G and the downstream along sense of rotation (C direction) that magnetic pole S3 is next to magnetic pole S1, arrange.In addition for removing magnetic pole N4 and the magnetic pole N5 of developer G, be immediately arranged side by side.In addition, magnetic pole S6 immediately magnetic pole N5 arranges, and this magnetic pole S6 is for carrying magnetic pole.In addition, magnetic pole S6 is arranged on the position corresponding to adjacent segment GP3.In addition, for transmitting the magnetic pole N7 of developer G, be arranged between magnetic pole S6 and magnetic pole S1.
On the other hand, as shown in Figure 2, rotate forward the development sleeve 210 of developer roll 200 and be arranged to make the direction of its turning axle follow the direction of the turning axle of photoreceptor 12 towards the surface of photoreceptor 12.Yet the rotation of this roller makes identical with the direction of motion of photoreceptor 12 with the direction of motion (D direction) at GP2 place, the opposed position of photoreceptor 12 at development sleeve 210.In addition, magnet roller 220 is arranged on development sleeve 210 inside, and forms magnetic field (referring to Fig. 3) by a plurality of magnetic poles along circumferential arrangement, and this magnetic field is circumferentially distributed in development sleeve 210 outsides.
As shown in Figures 2 and 3, in rotating forward the magnet roller 220 of developer roll 200, radially be provided with magnetic pole S1, magnetic pole N2, magnetic pole N3, magnetic pole S4 and magnetic pole N5, these magnetic poles are configured to five permanent magnets, and the S utmost point of described permanent magnet or the N utmost point are along the face side that is circumferentially formed on magnet roller 220 of development sleeve 210.In addition, in rotating forward developer roll 200, magnetic pole S1 is arranged on and GP2 place, the opposed position of photoreceptor 12, and this magnetic pole S1 is development magnetic pole (development main pole).In addition, rotate forward developer roll 200 by making developer G contact the electrostatic latent image by developer G development photoreceptor 12 with photoreceptor 12 with GP2 place, the opposed position of this photoreceptor 12.
For transmitting and remove the magnetic pole N2 of developer G, along sense of rotation (D direction), be next to magnetic pole S1 setting, the magnetic field of repelling each other that above mentioned removal is produced by magnetic pole N2 and N3 causes, for picking up the magnetic pole N3 of developer G, be next to magnetic pole N2 setting, and be next to magnetic pole N3 setting for transmitting the magnetic pole S4 of developer G.In addition, as the magnetic pole N5 that carries magnetic pole, being next to magnetic pole S4 arranges.Magnetic pole N5 is arranged in corresponding to the position of adjacent segment GP3 and magnetic pole S6 opposed, and this magnetic pole S6 is the conveying magnetic pole of above mentioned reverse rotation developer roll 100.
It should be noted, as shown in Figures 2 and 3, in the exemplary embodiment, as the magnetic pole S1 of the development magnetic pole of reverse rotation developer roll 100 with there is identical polarity (the S utmost point) as the magnetic pole S1 that rotates forward the development magnetic pole of developer roll 200.
Fig. 3 is the schematic diagram of reverse rotation developer roll 100 and the magnetic flux distribution of rotating forward developer roll 200 (size of magnetic flux density).In addition, through the rotation center K1 of the development sleeve 110 of reverse rotation developer roll 100 and photoreceptor 12 rotation center K3(referring to Fig. 1) straight line by straight dashed line L1, represented.In addition, through rotating forward the rotation center K2 of development sleeve 210 of developer roll 200 and the rotation center K3(of photoreceptor 12 referring to Fig. 1) straight line by straight dashed line L2, represented.
In the exemplary embodiment, center (center line) M1 as the magnetic pole S1 of the development magnetic pole of reverse rotation developer roll 100 is arranged to the upstream skew along sense of rotation C to straight dashed line L1.Equally, as center (center line) M2 of magnetic pole S1 that rotates forward the development magnetic pole of developer roll 200, be arranged to the upstream skew along sense of rotation D to straight dashed line L2.
In addition, as the magnetic pole S1 of the development magnetic pole of reverse rotation developer roll 100 with form such magnetic pole as the magnetic pole S1 that rotates forward the development magnetic pole of developer roll 200, its each angle [alpha] under half breadth is equally wide or wider with 30 °.
It should be noted, " angle [alpha] under half breadth " means at the magnetic pole magnetic pole S1 of development magnetic pole (in the exemplary embodiment as) and locates along the angular breadth of the peak flux density of magnetic flux distribution curve of normal direction or the part of the half value of maximum normal magnetic flux density (summit), as shown in Figure 4.
Next, will effect and the advantage of illustrative embodiments be described.
First, will the transmission of the developer G of developing apparatus 18 be described.
As shown in Figure 2, in developing apparatus 18, developer G is fed to and is rotated forward developer roll 200 by the first stirring transmission member 58 and the second stirring transmission member 60.Being supplied to the developer G that rotates forward developer roll 200 adheres on the surface of development sleeve 210 by magnetic pole N3 and magnetic pole S4.The developer G adhering to is transmitted by the rotation (D direction) of development sleeve 210, and layer forms member 62 and makes by the bed thickness that rotates forward the developer G that developer roll 200 keeps smooth.Then, make bed thickness smooth after, developer G is by distributing as carrying the magnetic pole N5 of magnetic pole and magnetic pole S6 rotating forward between developer roll 200 and reverse rotation developer roll 100 at adjacent segment GP3 place.In other words, a part of developer G is transported to reverse rotation developer roll 100 from rotating forward developer roll 200.
At adjacent segment GP3 place, being assigned to developer G in reverse rotation developer roll 100 is transmitted by the rotation (C direction) of the development sleeve 110 of reverse rotation developer roll 100.Then, be positioned at as the developer G at the magnetic pole S1 place of development magnetic pole namely toner at GP1 place, position, contact with photoreceptor 12, thereby by the electrostatic latent image of the toner development photoreceptor 12 of developer G.Developer G is removed after developing between magnetic pole N4 and magnetic pole N5, and separated from the surface of development sleeve 110.Separated developer G is guided by guide plate 64, and turns back to spatial accommodation 50B.
In contrast, at adjacent segment GP3 place, being assigned to the developer G that rotates forward in developer roll 200 is transmitted by the rotation (D direction) of development sleeve 210.The magnetic pole S1 place being positioned at as development magnetic pole that is to say that the developer G at GP2 place, position contacts with photoreceptor 12, thereby by the electrostatic latent image of the toner development photoreceptor 12 of developer G.Developer G is removed after developing between magnetic pole N2 and magnetic pole N3, from the surface separation of development sleeve 210 and fall, and turns back to spatial accommodation 50B.
It should be noted, rotate forward the toner image (electrostatic latent image) that developer roll 200 again develops and developed by reverse rotation developer roll 100, thereby only by the situation of reverse rotation developer roll 100 execution, compare in the total amount that increases the toner developing and improved picture quality with development.
For example, being formed near the density leading section of the toner image being formed by reverse rotation developer roll 100 reduces portion and continues to be developed by rotating forward developer roll 200, even be positioned at thus the toner that density reduces portion place and be also developed, and can obtain the effect of correcting image quality defect.In addition, for example, by rotating forward in the toner image that developer roll 200 forms, density reduces portion and tends to appear near the terminal part of toner image.Therefore yet first toner image is formed on terminal part place by reverse rotation developer roll 100, and can obtain the appearance suppressing by rotating forward the picture quality defect that developer roll 200 causes.
Here, in the exemplary embodiment, as the magnetic pole S1 of the development magnetic pole of reverse rotation developer roll 100 with there is identical polarity as the magnetic pole S1 that rotates forward the development magnetic pole of developer roll 200.Therefore, as shown in Figure 5, the magnetic field of the magnetic pole of reverse rotation developer roll 100 (development magnetic pole) S1 and the magnetic field that rotates forward magnetic pole (development magnetic pole) S1 of developer roll 200 form along the direction (referring to the R1 of Fig. 5) of repelling each other.Therefore, the magnetic field being formed by corresponding magnetic pole (development magnetic pole) S1 is dominant at position GP1 and GP3 place, and points to photoreceptor 12 for the bearing of trend of the magnetic brush of developer G.
In contrast, corresponding development magnetic pole as shown in Figure 6 has in the situation of comparative example of opposed polarity therein, corresponding development magnetic pole N1 and the magnetic field between development magnetic pole S1 form along attraction direction mutually, and mutual corresponding magnetic field connects (referring to the R2 of Fig. 6) between development magnetic pole.Therefore, for the bearing of trend of the magnetic brush of developer G, do not point to photoreceptor 12 but point to mutual corresponding development magnetic pole.
Therefore, to be similar to the mode of illustrative embodiments, by the development magnetic pole (magnetic pole S1) that makes the development magnetic pole (magnetic pole S1) of reverse rotation developer roll 100 and rotate forward developer roll 200, there is identical polar, the situation of comparative example from the magnetic pole that wherein develops with Fig. 6 of different polarity is compared, increased the development interlock width (contact width) along circumferential direction, in this development interlock width, developer G locates to contact with photoreceptor 12 at development magnetic pole (for the position GP1 of development section and at least one in GP2).In addition, increase the development interlock width (along the contact width of circumferential direction) between developer G and photoreceptor 12, thereby and improved developing property (will describing the improvement of developing property in detail after a while).
In addition,, as shown in Fig. 2,3 and 5, having between the magnetic pole S6 and magnetic pole S1 of identical polarity, be provided with the magnetic pole N7 with the polarity different from them.Thus, improve the ability that transmits developer G between the magnetic pole S6 of identical polar and magnetic pole S1 having.
In addition, as shown in Figure 3, in the exemplary embodiment, as center (center line) M1 of the magnetic pole S1 of the development magnetic pole of reverse rotation developer roll 100, be arranged to the upstream side skew towards straight dashed line L1 along sense of rotation C.Equally, as center (center line) M2 of magnetic pole S1 that rotates forward the development magnetic pole of developer roll 200, be also arranged to the upstream side skew towards straight dashed line L2 along sense of rotation D.In addition, the magnetic pole S1 of reverse rotation developer roll 100 and the magnetic pole S1 that rotates forward developer roll 200 form such magnetic pole, and its each angle [alpha] under half breadth is equally wide or wider with 30 ° (referring to Fig. 4) all.
In the situation that such structure approached by the magnetic pole S1 of the development magnetic pole as reverse rotation developer roll 100 and the magnetic field forming respectively as the magnetic pole S1 that rotates forward the development magnetic pole of developer roll 200, and therefore tends to influence each other in magnetic field.Therefore, the magnetic pole that develops therein has in the situation of comparative example of Fig. 6 of opposed polarity, and the phenomenon of the development magnetic pole of the directed mutual correspondence of magnetic brush has the further outstanding tendency that becomes.Therefore, the development interlock width (along the contact width of circumferential direction) between developer G and photoreceptor 12 is reduced more, and has thus the tendency on the larger impact of developing property.That is to say, tend to the image deflects that appearance is caused by little development interlock width (along the contact width of circumferential direction).
Therefore, in such structure, by the development magnetic pole (magnetic pole S1) that makes the development magnetic pole (magnetic pole S1) of reverse rotation developer roll 100 and rotate forward developer roll 200, there is identical polar, increase the development interlock width (along the contact width of circumferential direction) between developer G and photoreceptor 12, and improved developing property.As a result, can suppress the image deflects that caused by little development interlock width (along the contact width of circumferential direction).
The detailed description that developing property improves
Next, to be described in detail following situation,, the development magnetic pole of reverse rotation developer roll 100 (magnetic pole S1) and the development magnetic pole (magnetic pole S1) that rotates forward developer roll 200 have identical polar, increase thus the development interlock width (along the contact width of circumferential direction) between developer G and photoreceptor 12, and improved developing property.
First, the developing property to only having in the situation of the developing apparatus of reverse rotation developer roll (situation of rotating forward developer roll is not wherein set) is described.
Fig. 7 A shows half breadth (referring to Fig. 4) when the development magnetic pole of reverse rotation developer roll while being 40 °, 30 ° and 25 °, is maintained at the weight MOS(g/m of the per unit area of the developer on reverse rotation roller 100
2) and development interlock width (mm) between relation, between the photosensitive surface on the side face that described development interlock width is magnetic brush and photoreceptor along the contact width of circumferential direction.
In addition, Fig. 7 B shows half breadth (referring to Fig. 4) when the development magnetic pole of reverse rotation developer roll while being 40 °, 30 ° and 25 °, MOS (g/m
2) and developing performance DQA(μ C/m
2) between relation.
It should be noted, DQA(μ C/m
2) be to adhere to (developments) to the quantity of electric charge of the per unit area of the toner on photoreceptor, and by the product acquisition of developed toner weight (DMA) and the toner quantity of electric charge (Q/M).In addition, DQA(μ C/m
2) be set to one of them index of developing property, and developing performance is along with DQA becomes larger and becomes better.
From Fig. 7 A and Fig. 7 B, can see, when the half breadth of development magnetic pole is larger, DQA is also larger, and developing performance improves.In addition, the half breadth of development magnetic pole is associated with development interlock width (along the contact width of circumferential direction).Therefore,, by increasing half breadth, increase development interlock width.As a result, developing performance improves.
Next, by for only thering is the structure (hereinafter referred to as " 1-MAG ") of reverse rotation developer roll, wherein the magnetic pole that develops in the exemplary embodiment has the reverse rotation developer roll 100 of identical polar and rotates forward the structure (hereinafter referred to as " homopolarity 2-MAG ") of developer roll 200 and the developing property separately of situation (hereinafter referred to as " heteropole 2-MAG ") of comparative example that wherein above mentioned development magnetic pole has Fig. 6 of different magnetic poles is described.
The curve map of Fig. 8 shows the relation between MOS and development interlock width (along the contact width of circumferential direction) in the structure of 1-MAG, homopolarity 2-MAG and heteropole 2-MAG.The curve map of Fig. 9 shows the relation between MOS and developing performance DQA in the structure of 1-MAG, homopolarity 2-MAG and heteropole 2-MAG.In addition, in Fig. 8 and Fig. 9, the half breadth of development magnetic pole is all set as about 30 °.
It should be noted, the developing performance shown in Fig. 9 is the developing performance that 1-MAG structure and 2-MAG construct the only reverse rotation developer roll in these two structures.In other words, by before rotating forward the development of developer roll execution, only on reverse rotation developer roll, developed toner image has been carried out to measurement.
As the curve map from Fig. 8 can be seen, in the situation that its development magnetic pole has the heteropole 2-MAG(comparative example of opposed polarity), with 1-MAG(reverse rotation developer roll only) situation compare, greatly reduce development interlock width.In addition, large with respect to the variation of MOS development interlock width, and therefore can stably not form development interlock.In contrast, in the situation that its development magnetic pole has the homopolarity 2-MAG(illustrative embodiments of identical polarity), with 1-MAG(reverse rotation developer roll only) situation compare, development interlock width only reduces slightly, variation with respect to MOS development interlock width is little, and therefore stably forms development interlock.
In addition, as the curve map from Fig. 9 can be seen, in the situation that its development magnetic pole has the heteropole 2-MAG(comparative example of opposed polarity), with 1-MAG(reverse rotation developer roll only) situation compare, developing performance DQA is greatly diminished.In contrast, in the situation that its development magnetic pole has the homopolarity 2-MAG(illustrative embodiments of identical polarity), with 1-MAG(reverse rotation developer roll only) situation compare, developing performance DQA only reduces slightly.
As mentioned above, the magnetic pole that develops therein has in the situation of comparative example of opposed polarity, as shown in Figure 6, is formed on magnetic field between the development magnetic pole of mutual correspondence along attracting direction to form.Therefore, the bearing of trend of magnetic brush points to mutually corresponding development magnetic pole, and development interlock width reduces.As a result, developing property reduces.In contrast, the in the situation that of illustrative embodiments, because development magnetic pole has mutually identical polarity, as shown in Figure 5, therefore, the magnetic field being formed between the development magnetic pole of mutual correspondence forms along the direction of repelling each other.Thus, the bearing of trend of magnetic brush points to photoreceptor 12, and has stably guaranteed development interlock width.As a result, improved developing property.
In addition, in the curve map of the relation between the expression MOS shown in Fig. 9 and developing performance DQA, the magnetic pole that develops therein has in the comparative example of opposed polarity, even if DQA is also low under the MOS identical with J region.As shown in Figure 6, this magnetic field that shows to be formed between the development magnetic pole with opposed polarity forms along attraction direction, and the ability that transmits developer reduces, and has therefore occurred the transmission error (obstruction) of developer.
As mentioned above, the magnetic pole that develops therein has in the developing apparatus 18 of illustrative embodiments of identical polarity, the situation of comparative example with the magnetic pole that wherein develops with Fig. 6 of opposed polarity is compared, and has stably guaranteed development interlock width and has improved developing property.In addition, prevent or suppressed the transmission error of developer G.In addition, because transmit the ability of developer, improve, the amount that therefore flows into the developer G in developing regional (position GP1 and GP2) is stable.Therefore, suppress or prevented from being changed by cycle of influx the appearance of the nonhomogeneous density causing.
Other
It should be noted, the invention is not restricted to illustrative embodiments.
In the exemplary embodiment, as the magnetic pole S1 of the development magnetic pole of reverse rotation developer roll 100 with all form the S utmost point as the magnetic pole S1 that rotates forward the development magnetic pole of developer roll 200, but the invention is not restricted to this.These two magnetic poles can be the N utmost points.
In addition, for example, in the exemplary embodiment, rotate forward developer roll 200 and along the sense of rotation of photoreceptor 12, be arranged on the downstream of reverse rotation developer roll 100.Yet, the invention is not restricted to this.Rotate forward developer roll 200 and can be arranged on along the sense of rotation of photoreceptor 12 upstream of reverse rotation developer roll 100.
In addition, for example, in the exemplary embodiment, the quantity of the magnetic pole of the magnet roller 120 of reverse rotation developer roll 100 is 7, and the quantity of magnetic pole of rotating forward the magnet roller 220 of developer roll 200 is 5, but the invention is not restricted to this.When development magnetic pole has identical polar, the quantity of magnetic pole and the polarity of different magnetic poles are not limited to illustrative embodiments.
In addition, for example, in the exemplary embodiment, magnetic pole N7 is arranged on the magnetic pole S1 of development magnetic pole and carries between the magnetic pole S6 of magnetic pole, but the invention is not restricted to this.A plurality of magnetic poles can be arranged so that adjacent pole has opposed polarity.
In addition, for example, in the exemplary embodiment, image retaining member is the photoreceptor with drum shape, but the invention is not restricted to this.Image retaining member can be banded photoreceptor.
In addition, the structure of image forming apparatus is not limited to the structure of illustrative embodiments, and can take various structures.For example, image forming apparatus is single color printing type, but the invention is not restricted to this.This equipment can be colored printing type.In addition, the in the situation that of colored printing, can adopt such method,, in the method, each color toner image is all transferred to middle transfer body (such as intermediate transfer belt) and image is transferred to printed medium jointly from the photoreceptor 12 corresponding to every kind of color.
And, certainly, in the situation that not departing from technical scope of the present invention, can form various embodiments.
In order to illustrate and to describe the foregoing description that object provides illustrative embodiments of the present invention.Its object is not intended to exhaustive the present invention or limit the invention to disclosed precise forms.Obviously, many modifications and variations will be apparent for those skilled in the art.Selecting and describing embodiment is for principle of the present invention and its practical application are described best, thereby makes those skilled in the art can understand the present invention for various embodiments and have the various modifications that are suitable for contemplated concrete application.Scope of the present invention is intended to be limited by following claim and their equivalent.
Claims (5)
1. a developing apparatus, described developing apparatus comprises:
A pair of developer retaining member, this pair of developer retaining member comprises
A pair of cylindrical member, this pair of cylindrical member arranges close to each other, and rotates along equidirectional at adjacent segment place, and at described adjacent segment place, these two cylindrical members are closely close, and
A pair of magnetic force generating unit, this pair of magnetic force generating unit is arranged on respectively in described a pair of cylindrical member and produces for keeping the magnetic force of the developer on these cylindrical members; And
A pair of development magnetic pole, this pair of development magnetic pole is separately positioned in described a pair of magnetic force generating unit, is arranged to sub-image retaining member opposedly, and sets for and has identical polarity.
2. developing apparatus according to claim 1,
Wherein, described a pair of magnetic force generating unit is provided with a pair of conveying magnetic pole, the position arranged opposite that corresponds respectively to described adjacent segment of this pair of delivery magnetic utmost point, and set for and there is contrary polarity, and
Between described conveying magnetic pole and described development magnetic pole, one or more magnetic poles are set, make to there is different polarity when described development magnetic pole and described delivery magnetic have the magnetic pole that identical polarity chron is adjacent.
3. developing apparatus according to claim 1 and 2,
Wherein, described sub-image retaining member has the shape of tubular substantially, and
The center of described a pair of development magnetic pole is separately positioned on the upstream along sense of rotation of a straight dashed line, and described straight dashed line is through the rotation center of described cylindrical member and the rotation center of the described sub-image retaining member of cylindrical shape substantially.
4. an image forming apparatus, described image forming apparatus comprises:
According to the developing apparatus described in any one in claims 1 to 3;
Sub-image retaining member, described sub-image retaining member has for the surface that forms sub-image, and described sub-image is revealed as toner image by described developing apparatus; And
Transfer section, described transfer section is transferred to the lip-deep toner image that is formed on described sub-image retaining member on transfer printing target object.
5. an image forming method, described image forming method comprises:
By according to the developing apparatus described in any one in claims 1 to 3, the lip-deep sub-image that is formed on sub-image retaining member being revealed as to toner image; And
The lip-deep toner image that is formed on described sub-image retaining member is transferred on transfer printing target object.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JPJP2012-160813 | 2012-07-19 | ||
| JP2012-160813 | 2012-07-19 | ||
| JP2012160813A JP6051642B2 (en) | 2012-07-19 | 2012-07-19 | Developing device and image forming apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103576510A true CN103576510A (en) | 2014-02-12 |
| CN103576510B CN103576510B (en) | 2019-05-17 |
Family
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310114504.1A Expired - Fee Related CN103576510B (en) | 2012-07-19 | 2013-04-03 | Developing apparatus, image forming apparatus and image forming method |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US8892009B2 (en) |
| JP (1) | JP6051642B2 (en) |
| CN (1) | CN103576510B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2141048A (en) * | 1983-06-08 | 1984-12-12 | Xerox Corp | Electrostatographic magnetic brush development apparatus |
| JP2006146286A (en) * | 2006-03-06 | 2006-06-08 | Ricoh Printing Systems Ltd | Developing device |
| US20070212123A1 (en) * | 2006-03-06 | 2007-09-13 | Canon Kabushiki Kaisha | Developing apparatus and image forming apparatus |
| CN101281383A (en) * | 2007-04-03 | 2008-10-08 | 富士施乐株式会社 | Developing body, developing apparatus and image forming apparatus |
| JP4951223B2 (en) * | 2005-08-12 | 2012-06-13 | 株式会社リコー | Development device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3867751B2 (en) * | 1998-09-30 | 2007-01-10 | リコープリンティングシステムズ株式会社 | Image recording device |
| JP2005258315A (en) * | 2004-03-15 | 2005-09-22 | Ricoh Co Ltd | Developing device and picture formation apparatus |
| JP4528055B2 (en) * | 2004-08-06 | 2010-08-18 | 株式会社リコー | Developing device and image forming apparatus using the same |
| JP2006091425A (en) * | 2004-09-24 | 2006-04-06 | Ricoh Printing Systems Ltd | Developing device and electrophotographic apparatus using the same |
-
2012
- 2012-07-19 JP JP2012160813A patent/JP6051642B2/en active Active
-
2013
- 2013-01-29 US US13/753,052 patent/US8892009B2/en not_active Expired - Fee Related
- 2013-04-03 CN CN201310114504.1A patent/CN103576510B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2141048A (en) * | 1983-06-08 | 1984-12-12 | Xerox Corp | Electrostatographic magnetic brush development apparatus |
| JP4951223B2 (en) * | 2005-08-12 | 2012-06-13 | 株式会社リコー | Development device |
| JP2006146286A (en) * | 2006-03-06 | 2006-06-08 | Ricoh Printing Systems Ltd | Developing device |
| US20070212123A1 (en) * | 2006-03-06 | 2007-09-13 | Canon Kabushiki Kaisha | Developing apparatus and image forming apparatus |
| CN101281383A (en) * | 2007-04-03 | 2008-10-08 | 富士施乐株式会社 | Developing body, developing apparatus and image forming apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| US20140023409A1 (en) | 2014-01-23 |
| CN103576510B (en) | 2019-05-17 |
| JP2014021332A (en) | 2014-02-03 |
| JP6051642B2 (en) | 2016-12-27 |
| US8892009B2 (en) | 2014-11-18 |
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